Recently, more and more attention has been paid to a Machine-to-Machine (M2M) communication in the industry. This type of communication does not necessarily involve human interaction, and in comparison with the current human to human communication, it is aimed to different market scenarios. Since M2M is an integration of a wireless communication and an information technology, it can be used in a bi-directional communication for such as collecting information, setting parameters and sending instructions remotely, and thus the M2M technology may have different application schemes such as security monitoring, vending machine, remote meter reading, and so on. In terms of the number of terminals, it is anticipated that the terminals for a human to human communication may only occupy ⅓ of the whole market of terminals in the future, and a larger amount of communication will be machine-to-machine communication traffic. In fact, the number of machines today is at least 4 times that of humans, and therefore M2M has an enormous market potential.
Accordingly, respective international standardization organizations are all conducting studies on the M2M communication. Among others, 3GPP has set up special work group to study what optimization and improvement need to be made on the network architecture and the critical technology to support M2M applications. In 3GPP, such machine to machine communication is referred to as Machine-Type Communication, and is defined in Release 10. Since MTC devices involves features comprising low cost of manufacture and development, a potentially very large number of MTC devices and possibly a wide distribution, but the traffic per device is little. In comparison with the matured human-to-human or human-to-machine communication mechanisms, the MTC communication mechanism needs many refinements, optimizations and improvements. Currently, the traffic demand of MTC is under a further refinement, while the work on the optimization of MTC network architecture and the improvement of the critical technology just begun.
FIG. 1 shows a 3GPP service model for a machine-type communication. The 3GPP network may provide transport and communication services optimized for the machine-type communication. For example, an end-to-end application between MTC devices 101 and MTC servers 105 or other MTC devices may utilize 3GPP bearer services, SMS and IMS etc. provided by the 3GPP network. As is known to those skilled in the art, the 3GPP network may utilize a technology such as GSM, GPRS, WCDMA, TD-SCDMA etc., but the invention is not limited thereto.
An MTC device 101 is a user equipment for a machine-type communication, which may communicate with MTC servers 105 or other MTC devices, via 3GPP network's PLMN (Public Land Mobile Network), for example. In addition. MTC devices 101 may communicate with other entities locally (wirelessly, via PAN or hardware), to acquire data for performing processes or communicating with MTC servers 105 or other MTC devices.
As shown in FIG. 1, an interface on an MTCu reference point provides MTC devices 101 access to the 3GPP network, to support the transport of traffics of the user plane and the control plane. Via the MTCu reference point, the MTC device 101 may be connected to, for example, UTRAN, E-UTRAN, GERAN, I-WLAN etc. For example, the MTCu reference point could be based on Uu, Urn, Ww and LTE-Uu interfaces.
A MTC server 105 is an entity for implementing services for MTC user. The MTC servers 105 may communicate with PLMN itself and communicate with MTC device 101 via PLMN. MTC servers 105 may also have an interface that can be accessed by MTC users. The MTC users may have one or more MTC servers 105 that communicate with MTC devices of the MTC users.
As shown in FIG. 1, MTC servers 105 are connected to the 3GPP network via an interface on MTCi or MTCsms reference point. Through the MTCi reference point, the MTC servers 105 can be able to connect to the 3GPP network and communicate with MTC devices via 3GPP bearer services or IMS. For example, MTCi could be based on Gi, SGi, and Wi interface, MTCsms is a reference point that the MTC server uses to connect the 3GPP network and thus communicates with MTC devices via SMS.
In many cases, a group of MTC devices receive same MTC service contents. For example, a group of vending machines receive the same common configuration information; on-board GPS devices from a same manufacturer receive the same update of GPS map software; one out of a group of MTC devices wishes to share service content (e.g., voice and/or audio, video, multimedia, stream etc) with multiple other MTC devices. In such case, using unicast transmission is not efficient for resource allocation, especially when the number of MTC devices is large. It is therefore desired to design architecture for enabling a MTC device to receive same contents based on broadcast/multicast.
What is readily conceived is the existing multimedia broadcast/multicast service (MBMS) technology. MBMS is a point-to-multipoint traffic bearer capability introduced in Release 6 by the international standardization organization 3GPP. MBMS implements point-to-multipoint traffic in which one content source transmits contents to multiple users, through network resource sharing, including the resource sharing of the mobile core network and access network, especially a resource sharing of the air interface. MBMS can not only realize a multicast and broadcast of plain-text and low-rate messages, but can also realize multicast and broadcast of high-rate multimedia traffics.
However, in existing MBMS technology, to receive service contents, a terminal needs to periodically detect a session start procedure of MBMS traffics. For low-cost MTC device, this will lead to considerable power consumption. Therefore, there is a need to provide architecture and solutions to solve these problems and meet requirements of MTC.